1. Field of the Invention
The invention relates to a security system, comprising a central apparatus and at least one detector apparatus; the detector apparatus comprising transmission means for wirelessly transmitting a message comprising a source identification uniquely identifying the transmitting apparatus, and detection means for detecting an alarm condition and in response causing the transmission means to transmit a message; the central apparatus comprising: memory means for storing a source identification of at least one detector apparatus; alarm means for raising an alarm; user interface means for bringing the central apparatus in a selected one of a plurality of modes, including an operational mode and a learning mode; and reception means for receiving a wirelessly transmitted message, for storing, in the learning mode, the source identification of a received message in the memory means, and for causing, in the operational mode, the alarm means to raise an alarm if the source identification of a received message is stored in the memory means.
The invention further relates to a central apparatus, a detector apparatus, a confirmation apparatus, and a remote control for use in such a security system.
2. Description of Related Art
Traditionally detector apparatuses, such as burglar detectors, transmit an alarm message to a central apparatus of the security system via a wired connection when the detector apparatus detects an alarm condition. When the central apparatus receives an alarm message it uses alarm means, such as a siren or a light, to raise an alarm. Also silent alarm may be raised, for instance by triggering a remote security company or the police. Such systems are typically installed and maintained by professional companies. Similar systems of reduced complexity are available for domestic use and can be installed and maintained by a technically skilled consumer. With the continuing drop in cost and power requirements of electronic components and the liberalisation of the use of certain RF transmission bands, cost-effective cord-less security system have become available which can be installed and maintained by the general public. Such a system is known from the Home Security System, 1995 of Grundig. Each detector apparatus is locally powered, for instance, by a battery. The detector apparatus transmits a message via RF to the central apparatus, upon detecting an alarm condition, making the system fully cord-less. Unlike wired systems, the communication is, in principle, not restraint to the principal area to be protected by the system. Typically, the communication range is 30 meters, allowing the system to cover an area with a diameter of approximately 60 meters, with the central apparatus at the centre. In many domestic situations this implies that (parts of) neighbouring houses or apartments are included in this communication area, whereas, in general, the area to be protected is limited to a smaller area, such as one house or one apartment. To ensure that the central apparatus only responds to alarm messages transmitted by detectors, which are intended to be guarded and, for instance, not by detectors which are part of a neighbouring security system, a alarm message is only accepted if it is transmitted by a detector which is known to the central apparatus. Each apparatus has a unique communication address. Whenever a detector apparatus transmits an alarm message, the unique address is included in the alarm message as the source address of the message. Before an alarm message is accepted from a specific detector apparatus, the detector apparatus needs to be trained to the central apparatus. During the training, first the central apparatus is brought into a learning mode, by using a key to bring the central apparatus into the installation mode and pressing a button on the central apparatus to bring the central apparatus to a learning mode. Next, an alarm is triggered on the detector apparatus, which needs to be learned. Typically, a tamper alarm is triggered. Upon receiving the resulting alarm message, the central apparatus stores the source address of the received alarm message in a memory. The user can select the memory location in which a specific detector is stored. Using buttons on the central apparatus, the user can selectively disable or enable memory locations. Alarm messages from a detector apparatus, whose memory location has been disabled, are not acted upon by the central apparatus. In this ways, zones of a house, each covered by a detector apparatus, can selectively be guarded or not guarded. It is desired that the chance is reduced of an apparatus being trained, which should not be part of the system. In order to avoid that a neighbouring detector apparatus, which transmits an alarm message at the moment of the central apparatus being in the learning mode, is stored in the central apparatus, the Home Security System of Grundig requires a detector apparatus to be near the central apparatus for the detector apparatus to be accepted. Since the normal operational distance is larger, this requires the central apparatus to use different thresholds for receiving messages. Furthermore, limiting the operational distance provides no adequate protection in certain situations of, for instance terraced houses or apartments, where typically entrances are located immediately next to one another and central apparatuses and some detector apparatuses tend to be located in the entrance halls. Moreover, this requires detector apparatuses to be near the central apparatus and not at the location/zone where the detector apparatus is intended to operate. This increases the chance of the user, mistakenly, placing a detector apparatus in a different zone than programmed on the central apparatus. Since the alarm raised by the central apparatus, in the Grundig system, is specific for a memory location (and therefore for a zone), this may have a significant impact.
Among others, it is an object of the invention to provide a wireless security system with an improved routine for learning detector apparatuses. More specifically, it is an object to reduce the chance of a detector apparatus unwantedly being programmed into the central apparatus. A further object of the invention is to provide a wireless security system in which the detector apparatus can be programmed into the central apparatus from any location within the normal operating range of the system.